PHP回调:类的方法是否具有:: class的等效项? [英] PHP callback: Is there an equivalent for ::class for a method of a class?

问题描述

在PHP中，可以通过这样的类名称解析获得完整的类名称:

In PHP it is possible to get a full class name via class name resolution like this:

示例:

namespace Name\Space;
class ClassName {}

echo ClassName::class;

输出: Name \ Space \ ClassName

这比直接在代码中使用字符串 Name \ Space \ ClassName 更好，因为代码自省(尤其是在IDE中)可以直接找到错误.

This is better than using the string Name\Space\ClassName directly in the code because code introspection especially in IDEs can find an error directly.

我想知道类的方法是否有类似的东西-这对回调函数特别有用.

I wonder if there is something similar for methods of a class - this would be specifically useful for callback functions.

这基本上就是传递回调的方法:

This is how you can basically can pass a callback:

$a = function($callback,$arg) { return $callback($arg); }

$a('getInfo',5);

我宁愿做这样的事情，也不愿在这里传递字符串(可能会改变):

Instead of passing a string here (which might change), I would prefer to do something like this:

$a(MyClass::class::getInfo,5);

我声明"在IDE中单击，我可以直接转到 getInfo ，此外，如果方法不再存在，我会看到错误.有什么方法可以实现我在这里要做的事情?

With I "go to declaration" click in the IDE I could go directly to getInfo plus I see errors in case with method does not exist anymore. Is there a way to achieve what I want to do here?

推荐答案

实际上，您使用可调用类型.PHP只能将方法/函数名称设置为字符串.但是，如果您使用类和对象，则将有另一种设置回调的方法.例如:

In fact, you work with callable type. And PHP allows setting method/function name only as a string. But if you use classes and objects you will have a different way to set callback. For example:

$a = function($callback, $arg) { 
   return call_user_func($callback, $arg)); 
}

// call a static method of the class with 
// using fullname space and method name as a string
$a('Name\Space\MyClass::getInfo',5); 

// call a static method of the class 
// with using ::class 
$a([MyClass::class, 'getInfo'], 5);

// call a method of an object 
$myObject = new MyClass();
$a([$myOject, 'getInfo'], 5);

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